CooliPi can cool under 50˚C overclocked to 2350/750/550 MHz on air, with ambient temp 23˚C . Including GPIO with POE header on a side, CSI and DSI cables and two resets. Manufactured for one and a half years now. Only 8GB models can be pushed that far, because its PMIC runs at 1.5MHz, i.e. 50% higher than in former models. More energy per PMIC tick delivers more current to the SoC. This is the secret of the latter Raspi models' overclockability. You can even use it to cool it in liquid Nitrogen (video).